Cavitation, a major source of radiated noise from marine craft such as surface ships, increases the total noise generated during ship operation and reduces sonar sensing capability. Cavitation is also a source of ship hull vibration and a cause of surface erosion which increases maintenance costs. The marine craft rudder environment for the foregoing cavitation problems are set forth as background in prior U.S. Pat. Nos. 5,415,122 and 5,456,200 to one of the inventors of the present invention which has as an important object thereof the suppression of cavitation associated with cavitation patterns on the sides of a generally conventional or typical rudder on marine vessels.